With the constant evaluation of the wireless communication technology and standard, the mobile packet services are developed greatly, and the data throughput capacity of a single terminal has been promoted continually. With a Long Term Evolution (LTE) system as an example, the data transmission with a downlink maximum rate of 100 Mbps can be supported within a 20M bandwidth, and in the subsequent enhanced LTE (LTE Advanced) systems, the data transmission rate will be promoted, and it can even reach 1 Gbps.
The inflatable growth of data service volume of the terminal makes the relevant network resources become gradually scarce, and especially in a situation that the new generation communication technology (such as the 3G and LTE) still cannot be widely deployed in the network, it will be followed that the user rate and traffic demand cannot be satisfied, and the user experience becomes worse. How to prevent and change the situation is a problem that must be considered by the operators, on one hand, it is required to accelerate the promotion and network deployment of the new technology; on the other hand, it is wished to perform enhancement on the related networks and technologies, to achieve the object of rapidly promoting the network performance. As is known to all, besides the wireless network technology provided in the 3rd Generation Partnership Project (3GPP), the Wireless Local Area Network (WLAN) that has been universally applied at present, especially the wireless local area network based on the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard, has been widely applied to the hotspot access coverage in the family, enterprise and even internet. Wherein the technical specifications proposed by the wireless fidelity WiFi alliance (Wi-Fi Alliance) is most widely applied, thus a WiFi network is frequently equal to the WLAN network based on the IEEE 802.11 standard in practice, and in the condition of not causing a confusion, a WiFi module is also adopted to describe a wireless transceiving and processing module supporting the WLAN in the network nodes below.
In this premise, certain operators and companies have proposed to converge the WLAN with the related 3GPP network to implement the joint transmission, to achieve the object of the load distribution and network performance improvement. Even though the 3GPP has made the related protocols for Interworking between the 3GPP network and the WLAN network at present, a plurality of shortcomings still exist in the current Interworking architecture, for example, the handover of data streams is comparatively slow when a terminal User Equipment (UE) moves between the 3GPP network and the WLAN network, moreover, the data streams of the two networks are all required to go through the network elements of the 3GPP core network under this case, which causes the heavier load. In addition, another very important point is that the current architecture is still dependent on that the operator can have an independent 3GPP network and an independent and complete WLAN network, and this requires that the operator should simultaneously operate and maintain a plurality of networks, so that the operation Capital Expenditure (CAPEX) is higher. Therefore, the convergence demand of the WLAN and the 3GPP network is proposed again, and a new solution has also been gradually proposed and discussed.
The 3GPP SA2 passes the Access Network Discovery Support Functions (ANDSF) scheme, which provides a mode of selecting a target access network for the terminal according to the operator's policy.
The ANDSF standard is defined in the 3GPP R10, and the ANDSF serves as an access anchor point to implement the intelligent network selection, and through the interactive collaboration between the network and the terminal, implements the effective distribution of the network access, which conforms to the operating direction of the cooperative networking in the future. The ANDSF makes policies based on information including the network load, terminal capability and user subscription condition and so on, and helps the terminal user select the optimal network type for accessing, which implements the collaborative operation of a plurality of access ways. The ANDSF can be separately deployed, and it also can be jointly set with other network elements. At present, the industry mainstream viewpoint considers the scheme that the ANDSF can be deployed on the PCC device.
The ANDSF is a WLAN interworking scheme based on the core network, and it does not consider the influence on the access network, moreover, since the ANDSF is a relatively static scheme, it cannot adapt well to the situation of the dynamic changes of the network load and channel quality, thus the WLAN interworking discussion is also carried out in the 3GPP access network group.
Three basic candidate WLAN interworking schemes of the access network side are passed in latest 3GPP RAN2 conference (RAN2#81bis).
In scheme 1, the 3GPP access network side provides auxiliary information, and the terminal decides how to migrate services to the WLAN or the 3GPP access network according to the auxiliary information and rules provided by network elements (such as the ANDSF) except the access network. In the scheme, a decision-making entity for interworking between the 3GPP access network and the WLAN is located at the UE.
In scheme 2, the 3GPP access network side provides access network selection parameters (such as a threshold, a priority and a rule and so on) for the terminal, and the terminal decides how to migrate services to the WLAN or the 3GPP access network based on these parameters. In the scheme, a decision-making entity for interworking between the 3GPP access network and the WLAN is divided into: a rule making entity for interworking between the 3GPP access network and the WLAN and a process triggering entity for interworking between the 3GPP access network and the WLAN. Wherein, the rule making entity for interworking between the 3GPP access network and the WLAN is located at the 3GPP access network side, and the process triggering entity for interworking between the 3GPP access network and the WLAN is located at the UE side. The 3GPP access network side is responsible for making rules for interworking between the 3GPP access network and the WLAN, and the UE decides when an interworking process between the 3GPP access network and the WLAN is triggered according to the rules of the 3GPP access network side, and then in combination with its own practical WLAN measurement results and the rules of the 3GPP access network side, decides a target access network (the 3GPP network or the WLAN) and services required to be migrated.
In scheme 3, with regard to a terminal in a radio resource control RRC connection state (a long term evolution LTE system) or a CELL_DCH state (a universal mobile telecommunications system (UMTS)), the 3GPP access network side decides how the terminal to migrate services to the WLAN or the 3GPP access network, and informs the terminal. With regard to a terminal in an RRC IDLE state (the LTE system) or a CELL_PCH state or URA_PCH state (the UMTS system), the way of the scheme 2 is adopted. In the scheme, a decision-making entity for interworking between the 3GPP access network and the WLAN is located at the 3GPP access network side, and the UE side has a process triggering entity for interworking between the 3GPP access network and the WLAN (only enabled when the UE is in the RRC IDLE state (the LTE system) or the CELL_PCH state or URA_PCH state (the UMTS system).
In the above schemes, only the basic flow of the WLAN interworking is defined, but the power consumption problem of the terminal caused by the WLAN searching and interworking is not discussed. Considering that the terminal is required to execute the scanning measurement of a WLAN AP when selecting a WLAN network, and it is required to open a WLAN channel when deciding to migrate the services to the WLAN, the power consumption of the behavior is very high, and the 3GPP network side defaults to consider a user experience priority principle at present when making the discovery or search (WLAN discovery) and offload rules, and the terminal power saving is normally not taken as a preferentially considered index.
For example, a WLAN offload rule frequently used by the operators is that: when the terminal enters the coverage scope of the WLAN, the network side triggers an interworking process between the 3GPP access network and the WLAN, and requires the UE to measure and scan the WLAN, to search the WLAN and decide whether services can be migrated to improve the throughput of the UE and reduce the load of the 3GPP network, and the rule can guarantee that the UE discovers the WLAN in the first time and transfers all or part of services to the WLAN as soon as possible, to improve the user experience and reduce the load of the 3GPP network. But the rule is extremely disadvantageous to the power saving of the UE, in many cases, since the UE entering the coverage scope of the WLAN does not represent that the UE has services required to be transmitted currently or services required to be migrated, and in the case that the UE has executed the WLAN searching and even established a connection with the WLAN, but it has no services required to be migrated, the behavior of the previous WLAN searching is wasted, which additionally increases the power consumption of the UE. Especially in the case that WLAN access points are continually increased in the future, the above rule will aggravate the power consumption of the UE.
A scheme has been passed in the 3GPP RAN2, when the UE has a power-saving tendency, a Power Preference Indication (PPI) of the UE can be triggered, and the PPI is sent to an access network node of a service network, and the access network node can adjust configuration parameters of the Discontinuous Reception (DRX) mechanism of the UE according to this. But with regard to other mechanisms, there is no power-saving processing at all.